Exercise bike



FIG. 1 is a top, front, right side perspective view of an exercise bike, showing my design.

FIG. 2 is a bottom, rear, left side perspective view thereof.

FIG. 3 is a front elevation view thereof.

FIG. 4 is a rear elevation view thereof.

FIG. 5 is a left side elevation view thereof.

FIG. 6 is a right side elevation view thereof.

FIG. 7 is a top plan view thereof.

FIG. 8 is a bottom plan view thereof.

FIG. 9 is an enlarged view of an area labeled 9 in FIG. 1.

FIG. 10 is an enlarged view of an area labeled 10 in FIG. 1; and,

FIG. 11 is an enlarged view of an area labeled 11 in FIG. 2.

The details shown in broken lines form no part of the claimed design. 

CLAIM The ornamental design for an exercise bike, as shown and described. 